A new benchmark: local mucosal immunisation improves where standard peripheral TB vaccination fails

31 May 2017

The only vaccine available for tuberculosis (TB) today - M.bovis Bacille Calmette-Guérin, or BCG for short - is known to be variably protective in different human populations. In particular, epidemiology studies show that adolescents and adults in high-burden TB areas do not benefit from standard intradermal BCG vaccination at all, whereas on the other hand adult vaccination in low mycobacterial exposure areas can lead to protective immunity.

Also in our non-human primate modelling efforts we have been finding variable outcome of BCG vaccination measured by protection of disease when using animal cohorts of different origin. Recently, we have been able to establish by systematic head-to-head analysis that, in a cohort where standard intradermal BCG vaccination fails, local mucosal (read: lung) administration of BCG does improve prognosis and protects from TB disease.

This finding provides a great new benchmark. It spurred already new lines of investigation into alternative administration routes and local pulmonary host response mechanisms in particular. Most importantly, in the light of the global health challenge to push back on the continuing TB pandemic, it also provides some ensuring evidence that we can improve upon the current BCG prophylaxis. We do have some positive benchmark now that allows to continue our TB vaccine research and development activities with a reasonable expectation that one day we will make a difference in preventing TB disease more effectively.